Geriba Swell Statistics, Junho: All Swell – Any Wind

The rose diagram illustrates the variation of swells directed at Geriba over a normal June and is based upon 2786 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Geriba. In this particular case the best grid node is 26 km away (16 miles).

The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 1.5% of the time. Green and yellow represent increasing swell sizes and red shows the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell occurs.

The diagram implies that the most common swell direction, shown by the biggest spokes, was SSE, whereas the the most common wind blows from the ENE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Geriba and offshore. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Geriba, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical June, swells large enough to cause surfable waves at Geriba run for about 98% of the time.

IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.